In recent years, in the field of machining, automation has advanced for labor saving and improvement of productivity. As a machine tool in which automation, such as automatic control by an NC program, automatic tool change by a tool changer, or automatic pallet change by a pallet changer, has been achieved, the machine tool disclosed in Japanese Unexamined Patent Publication No. 2006-326740 is conventionally known, for example.
In this machine tool, a series of machining operations is performed on the workpiece on the pallet, while tools are changed by the tool changer. When the machining of the workpiece has been completed, the pallet on which the machined workpiece is placed is changed by the pallet changer for another pallet on which an unmachined workpiece is placed, and then a series of machining operations is performed on the unmachined workpiece. Thus, a predetermined number of workpieces are successively machined.